Has anything been changed in the house circuitry? Has the washer always worked ok until now?
Electrical surges can be enough to trip an RCD; pumps, motors and heating elements are prime candidates here
If nothing has changed and the problem has only just started then you may well need an electrician. They can test the RCD for nuisance tripping to make sure that it’s working correctly
If the RCD checks out then it will be a fault with either the circuit or the washer. It could be as simple as a sticky bearing in the washer motor causing a surge to get the motor moving
It’ll be a logical process but time-consuming